﻿/*
 * Copyright (c) 2015-2016 Constantijn Evenhuis (blueprints@const.nl)
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
using Blueprints.Editing.Actions;
using System.Collections.Generic;

namespace Blueprints.Editing
{
    partial class EditContext
    {
        private readonly Stack<IUndoableAction> undo = new Stack<IUndoableAction>();
        private readonly Stack<IUndoableAction> redo = new Stack<IUndoableAction>();

        /// <summary>
        /// Gets whether an action is available to redo.
        /// </summary>
        public bool CanRedo
        {
            get
            {
                return redo.Count > 0;
            }
        }

        /// <summary>
        /// Gets whether a action is available to undo.
        /// </summary>
        public bool CanUndo
        {
            get
            {
                return undo.Count > 0;
            }
        }

        /// <summary>
        /// Redoes the last undone action.
        /// </summary>
        public void Redo()
        {
            if (redo.Count == 0)
            {
                return;
            }

            IUndoableAction action = redo.Pop();
            undo.Push(action);
            EditNode node = action.Do();
            Synchronize(node);
        }
        
        /// <summary>
        /// Undoes the last action.
        /// </summary>
        public void Undo()
        {
            if (undo.Count == 0)
            {
                return;
            }

            IUndoableAction action = undo.Pop();
            redo.Push(action);
            EditNode node = action.Undo();
            Synchronize(node);
        }

        internal EditNode Do(IUndoableAction action)
        {
            redo.Clear();
            undo.Push(action);
            EditNode node = action.Do();
            Synchronize(node);
            return node;
        }
    }
}